Adjustable bridges of various types have been utilized with stringed musical instruments for a number of years. Several prior art bridge devices have been proposed which include individual bridge elements corresponding to each string of the instrument. A number of these prior art devices provide for individual adjustment of the bridge elements in one or more directions relative to the strings in order to achieve proper intonation and action adjustment of the strings. Such a mechanism allows the strings to be finely tuned and individually adjusted for personal taste or slight deviations in the trueness of the strings.
For example, Fender, U.S. Pat. No. 3,290,980 describes a bridge construction including a plurality of hardened steel sleeves arranged in end-to-end contacting relationship. The position of each sleeve may be individually adjusted longitudinally with respect to the string by a screw, and the height of the sleeves can be adjusted with respect to the body of the instrument by raising or lowering a supporting bridge section.
Similar devices are disclosed in Fender, U.S. Pat. No. 4,031,799 and Fender, U.S. Pat. No. 4,281,576. In these two references, a plurality of drums are positioned in end-to-end relationship, and each drum may be adjusted in two orthogonal directions so as to separately adjust the length of each string and the height of each string relative to the neck of the instrument. In each of these patents, the height adjustment requires that two separate set screws be adjusted for each drum in order to adjust the height of the string relative to the instrument.
Another prior art approach is disclosed in Schaller, U.S. Pat. No. 4,361,068. In this device, a series of movable pedestals are adjustable in two directions, and a threaded roller allows further adjustment of the string position laterally with respect to the guitar. The individual pedestals may be raised and lowered with respect to the body of the guitar by turning a pair of screws.
Several additional prior art devices are described in patents to Wilson et al., U.S. Pat. No. 4,373,417, McCarty, U.S. Pat. No. 2,714,326, Lieber, U.S. Pat. No. 4,248,126, Shaw et al., U.S. Pat. No. 4,385,543, and Petillo, U.S. Pat. No. 4,128,033.
In general, adjustment of the bridge units in the above prior art devices is somewhat difficult and time-consuming in view of the number of adjustment screws which must be utilized to move the individual bridge elements. In addition, these prior art devices generally do not incorporate a tuning mechanism, since the tuning of the strings in the prior art instruments is typically done at the neck extremity of the instrument, rather than on the body of the instrument.
In addition, these prior art devices generally allow the bridge elements to float, thereby requiring a spring or other biasing means to maintain the bridge element in its general position with respect to the longitudinal adjusting screw. This allows for greater relative motion of the bridge elements and less accurate adjustment of the bridge element position.
Accordingly, it is a primary object of this invention to improve the accuracy and ease of adjustment of a bridge for a stringed musical instrument.
It is a further object of this invention to reduce the number of adjustments which must be made in order to move an individual bridge element in an adjustable bridge.
Yet another object of the invention is to provide positive engagement for individual bridge elements of an adjustable bridge to reduce relative motion thereof.
A still further object of the invention is to combine a tuning mechanism with an adjustable bridge to improve accuracy and convenience in tuning, and for simplifying the replacement of the strings of a stringed musical instrument.
Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.